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Q-Initial Grid Bias Voltage Setting

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jamie danter
Posted on Tuesday, March 26, 2002 - 11:54 pm:   

Completed the cap job on the HD130.
Prior to installing the tube finals,
I checked operating voltages.
Bias circuit output is good and stable.

Question:
Should I set the bias circuit output V to
max volts @ Pin #5 grid,
to prevent excessive current flow in the tubes,
then adjust, reduce bias V, until 0.5V is reached at Point Y, Pin #8 cathode ???
Sure would hate to burn up a new set of tubes.
Thanks
Steve Kennedy
Posted on Monday, April 01, 2002 - 04:33 pm:   

Usually the bias point of the amp is in the ballpark to start with. It shouldn't be necessary to minimize the current flow before you work your way up to the correct setting.

Tubes are very forgiving compared to transistors! As long as the plates aren't glowing red, the bias should be in a safe region from which to proceed.

Steve